DIFFERENTIAL DIAGNOSIS IN LEARNING DISABILITIES

Summary

Principal Investigator: Richard K Olson
Affiliation: University of Colorado
Country: USA
Abstract: The long-range objectives of the Colorado Learning Disabilities Research Center (CLDRC) are the identification, characterization, validation and amelioration of reading disabilities and ADHD, the two most prevalent and often co-morbid disorders of childhood. To accomplish these objectives, the CLDRC employs a unique approach that assesses the extent to which genetic and environmental influences underlie these disorders, and that uses covariation in etiology to understand whether deficits in component skills of reading are manifestations of a single syndrome or represent separate subtypes. Test batteries that include psychometric measures of cognitive and academic abilities (Project I), reading, writing, and language processes (Project II), and ADHD and executive functions (Project III) will be administered to a sample of identical and fraternal twins and their siblings in which at least one member of each twin pair has a reading disability, to an independent sample of twins and their siblings in which at least one member of each twin pair has ADHD, and to a comparison group of twins and their siblings with no school history of reading disabilities or ADHD. Resulting data will be used to assess the etiologies of reading deficits (including word recognition skills, reading fluency, comprehension, and writing), ADHD, and their comorbidity, as well as their covariation with measures of phoneme awareness, phonological decoding, orthographic coding, vocabulary, listening comprehension, and executive functions. In order to map quantitative trait loci that influence learning disabilities, and conduct association and mutation analyses, blood samples will be obtained from families of all twin pairs (Project IV). Project V will assess response to computer-assisted instruction in 3 samples: early (K-4th) at-risk readers, 2nd - 4th grade twins identified with reading disabilities in Projects l-lll, and 4th grade twins with reading disabilities for whom we have extensive longitudinal assessments starting from preschool. Response to instruction in project V will also be studied in the Project IV molecular-genetic analyses. An administrative core unit will be responsible for coordinating the activities of the five research projects, ascertaining and scheduling subjects, obtaining questionnaire data and blood samples, and administering the Center budget. Reading disabilities and ADHD are important public health problems. The proposed research will advance our understanding of their etiology and remediation.
Funding Period: 2006-03-10 - 2010-11-30
more information: NIH RePORT

Top Publications

  1. pmc Reading comprehension in children with ADHD: cognitive underpinnings of the centrality deficit
    Amanda C Miller
    Vanderbilt University, 110 Magnolia Circle, Nashville, TN 37203, USA
    J Abnorm Child Psychol 41:473-83. 2013
  2. pmc Subtypes of developmental dyslexia: testing the predictions of the dual-route and connectionist frameworks
    Robin L Peterson
    University of Denver, Department of Psychology, Denver, CO, USA
    Cognition 126:20-38. 2013
  3. pmc The prevalence of DSM-IV attention-deficit/hyperactivity disorder: a meta-analytic review
    Erik G Willcutt
    Department of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USA
    Neurotherapeutics 9:490-9. 2012
  4. pmc Multiple regression analysis of reading performance data from twin pairs with reading difficulties and nontwin siblings: the augmented model
    Sally J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA
    Twin Res Hum Genet 15:116-9. 2012
  5. pmc Validity of DSM-IV attention deficit/hyperactivity disorder symptom dimensions and subtypes
    Erik G Willcutt
    Department of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USA
    J Abnorm Psychol 121:991-1010. 2012
  6. pmc A cross-lagged model of the development of ADHD inattention symptoms and rapid naming speed
    Anne B Arnett
    Department of Psychology, University of Denver, Frontier Hall 2155 S Race St, Denver, CO 80208, USA
    J Abnorm Child Psychol 40:1313-26. 2012
  7. pmc Test differences in diagnosing reading comprehension deficits
    Janice M Keenan
    1University of Denver, Denver, CO, USA
    J Learn Disabil 47:125-35. 2014
  8. pmc The aromatase gene CYP19A1: several genetic and functional lines of evidence supporting a role in reading, speech and language
    Heidi Anthoni
    Department of Medical Genetics, Biomedicum, University of Helsinki, 00014, Helsinki, Finland
    Behav Genet 42:509-27. 2012
  9. pmc Predicting word reading and comprehension with executive function and speed measures across development: a latent variable analysis
    Micaela E Christopher
    Department of Psychology and Neuroscience, University of Colorado Boulder, CO 80309, USA
    J Exp Psychol Gen 141:470-88. 2012
  10. pmc Colorado Twin Registry: an update
    Sally Ann Rhea
    Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
    Twin Res Hum Genet 16:351-7. 2013

Scientific Experts

Detail Information

Publications76

  1. pmc Reading comprehension in children with ADHD: cognitive underpinnings of the centrality deficit
    Amanda C Miller
    Vanderbilt University, 110 Magnolia Circle, Nashville, TN 37203, USA
    J Abnorm Child Psychol 41:473-83. 2013
    ....
  2. pmc Subtypes of developmental dyslexia: testing the predictions of the dual-route and connectionist frameworks
    Robin L Peterson
    University of Denver, Department of Psychology, Denver, CO, USA
    Cognition 126:20-38. 2013
    ..Further, a subset of controls could read normally despite impaired orthographic coding. The findings are discussed in terms of improvements to both models that might help better account for all cases of developmental dyslexia...
  3. pmc The prevalence of DSM-IV attention-deficit/hyperactivity disorder: a meta-analytic review
    Erik G Willcutt
    Department of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USA
    Neurotherapeutics 9:490-9. 2012
    ..These results provide important support for the diagnostic validity of ADHD, and argue against the hypothesis that ADHD is a cultural construct that is restricted to the United States or any other specific culture...
  4. pmc Multiple regression analysis of reading performance data from twin pairs with reading difficulties and nontwin siblings: the augmented model
    Sally J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA
    Twin Res Hum Genet 15:116-9. 2012
    ..36) may be substantially greater than those for less contemporaneous twin-sibling pairs (.14)...
  5. pmc Validity of DSM-IV attention deficit/hyperactivity disorder symptom dimensions and subtypes
    Erik G Willcutt
    Department of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USA
    J Abnorm Psychol 121:991-1010. 2012
    ..PsycINFO Database Record (c) 2012 APA, all rights reserved)...
  6. pmc A cross-lagged model of the development of ADHD inattention symptoms and rapid naming speed
    Anne B Arnett
    Department of Psychology, University of Denver, Frontier Hall 2155 S Race St, Denver, CO 80208, USA
    J Abnorm Child Psychol 40:1313-26. 2012
    ..Likewise, inattention symptoms have a small but significant predictive effect on subsequent rapid naming. The findings support a reciprocal relationship between naming speed and ADHD inattentive symptoms...
  7. pmc Test differences in diagnosing reading comprehension deficits
    Janice M Keenan
    1University of Denver, Denver, CO, USA
    J Learn Disabil 47:125-35. 2014
    ..Theoretical and practical implications of these test differences in defining and diagnosing comprehension deficits are discussed. ..
  8. pmc The aromatase gene CYP19A1: several genetic and functional lines of evidence supporting a role in reading, speech and language
    Heidi Anthoni
    Department of Medical Genetics, Biomedicum, University of Helsinki, 00014, Helsinki, Finland
    Behav Genet 42:509-27. 2012
    ..An aromatase inhibitor reduced dendritic growth in cultured rat neurons. From this broad set of evidence, we propose CYP19A1 as a candidate gene for human cognitive functions implicated in reading, speech and language...
  9. pmc Predicting word reading and comprehension with executive function and speed measures across development: a latent variable analysis
    Micaela E Christopher
    Department of Psychology and Neuroscience, University of Colorado Boulder, CO 80309, USA
    J Exp Psychol Gen 141:470-88. 2012
    ..These results have implications for understanding why reading comprehension and word reading are highly correlated yet separable..
  10. pmc Colorado Twin Registry: an update
    Sally Ann Rhea
    Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
    Twin Res Hum Genet 16:351-7. 2013
    ..The development of the CTR is an ongoing and evolving process, and it has proven to be a valuable registry, relatively representative of the population from which it was drawn...
  11. pmc Shared etiology of phonological memory and vocabulary deficits in school-age children
    Robin L Peterson
    University of Denver, CO, USA
    J Speech Lang Hear Res 56:1249-59. 2013
    ..The goal of this study was to investigate the etiologic basis for the association between deficits in phonological memory (PM) and vocabulary in school-age children...
  12. pmc Cognitive and behavioral indicators of ADHD symptoms prior to school age
    Anne Bernard Arnett
    Clinical Child Psychology, University of Denver, Denver, CO, USA
    J Child Psychol Psychiatry 54:1284-94. 2013
    ....
  13. pmc Alleles of a polymorphic ETV6 binding site in DCDC2 confer risk of reading and language impairment
    Natalie R Powers
    Department of Genetics, Yale University, 464 Congress Avenue, Suite 243, New Haven, CT 06520, USA
    Am J Hum Genet 93:19-28. 2013
    ..On the basis of these data, we propose a new name for BV677278: "READ1" or "regulatory element associated with dyslexia 1." ..
  14. pmc The genetic and environmental etiologies of individual differences in early reading growth in Australia, the United States, and Scandinavia
    Micaela E Christopher
    Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA
    J Exp Child Psychol 115:453-67. 2013
    ..In addition, the timing of the start of formal literacy instruction may affect the etiology of individual differences in early reading development but have only limited influence on the etiology of individual differences in growth...
  15. pmc Longitudinal stability and predictors of poor oral comprehenders and poor decoders
    Sa Elwér
    Department of Behavioral Sciences and Learning, Linkoping University, 581 83 Linkoping, Sweden
    J Exp Child Psychol 115:497-516. 2013
    ..Implications of the predictive stability of our results for identification and intervention of these important subgroups are discussed...
  16. pmc Comorbidity between reading disability and math disability: concurrent psychopathology, functional impairment, and neuropsychological functioning
    Erik G Willcutt
    1University of Colorado at Boulder, Boulder, CO, USA
    J Learn Disabil 46:500-16. 2013
    ....
  17. pmc Genotype by environment interactions in cognitive ability: a survey of 14 studies from four countries covering four age groups
    Dylan Molenaar
    Psychological Methods, Department of Psychology, University of Amsterdam, Weesperplein 4, 1018 XA, Amsterdam, The Netherlands
    Behav Genet 43:208-19. 2013
    ..However, a clear and general conclusion about the presence of a genuine G×E is hampered by differences between the individual studies with respect to environmental and genetic influences on cognitive ability...
  18. pmc A multiple deficit model of reading disability and attention-deficit/hyperactivity disorder: searching for shared cognitive deficits
    Lauren M McGrath
    Massachusetts General Hospital Harvard Medical School, USA University of Denver, USA
    J Child Psychol Psychiatry 52:547-57. 2011
    ..This study tests a multiple cognitive deficit model of reading disability (RD), attention-deficit/hyperactivity disorder (ADHD), and their comorbidity...
  19. pmc Identification of candidate genes for dyslexia susceptibility on chromosome 18
    Thomas S Scerri
    Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
    PLoS ONE 5:e13712. 2010
    ..Until now, no candidate genes have been identified to explain this linkage. Here, we set out to identify the gene(s) conferring susceptibility by a two stage strategy of linkage and association analysis...
  20. pmc Etiology and neuropsychology of comorbidity between RD and ADHD: the case for multiple-deficit models
    Erik G Willcutt
    Department of Psychology, University of Colorado, Boulder, CO 80309, USA
    Cortex 46:1345-61. 2010
    ..Attention-deficit/hyperactivity disorder (ADHD) and reading disability (RD) are complex childhood disorders that frequently co-occur, but the etiology of this comorbidity remains unknown...
  21. pmc Etiologies and molecular mechanisms of communication disorders
    Shelley D Smith
    Department of Pediatrics and Munroe Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE 68198 5960, USA
    J Dev Behav Pediatr 31:555-63. 2010
    ..When combined with careful phenotypic studies, molecular genetic studies have the potential to refine the clinical definitions of communication disorders and influence their remediation...
  22. pmc Understanding the complex etiologies of developmental disorders: behavioral and molecular genetic approaches
    Erik G Willcutt
    Department of Psychology and Neuroscience, University of Colorado at Boulder, Boulder, CO 80309, USA
    J Dev Behav Pediatr 31:533-44. 2010
    ..Implications of the results for these specific disorders and for developmental disabilities as a whole are discussed, and novel directions for future research are highlighted...
  23. pmc A family based association study of DRD4, DAT1, and 5HTT and continuous traits of attention-deficit hyperactivity disorder
    L Cinnamon Bidwell
    Department of Psychiatry and Human Behavior, Brown University, Box G S121 4, Providence, RI 02912, USA
    Behav Genet 41:165-74. 2011
    ..These results use novel methods to build upon important connections between dopamine genes and their final behavioral manifestation as symptoms of ADHD...
  24. pmc DeFries-Fulker analysis of longitudinal reading performance data from twin pairs ascertained for reading difficulties and from their nontwin siblings
    Raven L Astrom
    Institute for Behavioral Genetics, University of Colorado, 447 UCB, Boulder, CO 80309, USA
    Behav Genet 41:660-7. 2011
    ..However, tests for special twin environmental influences were nonsignificant...
  25. pmc Understanding the centrality deficit: insight from foreign language learners
    Amanda C Miller
    Department of Psychology, University of Denver, 2155 S Race St, Denver, CO 80208, USA
    Mem Cognit 39:873-83. 2011
    ..Readers with less L2 proficiency who did not have PK of the topic displayed a centrality deficit, relative to their L1 recall, but this deficit dissipated when they did possess PK...
  26. pmc Colorado Learning Difficulties Questionnaire: validation of a parent-report screening measure
    Erik G Willcutt
    Department of Psychology and Neuroscience, UCB 345, University of Colorado, Boulder, CO 80309, USA
    Psychol Assess 23:778-91. 2011
    ..Results are also promising for the other 4 CLDQ scales, but additional research is needed to refine each of these measures...
  27. pmc Gene by environment interactions influencing reading disability and the inattentive symptom dimension of attention deficit/hyperactivity disorder
    Jenni Rosenberg
    Department of Psychology, University of Denver, Denver, CO 80208 0001, USA
    J Child Psychol Psychiatry 53:243-51. 2012
    ..However, previous research indicates that RD and ADHD enter into opposite gene by environment (G × E) interactions...
  28. pmc Developmental dyslexia
    Robin L Peterson
    Department of Psychology, University of Denver, Denver, CO 80208, USA
    Lancet 379:1997-2007. 2012
    ..Six predisposing candidate genes have been identified, and evidence shows gene by environment interaction...
  29. pmc Predicting reading and spelling difficulties in transparent and opaque orthographies: a comparison between Scandinavian and US/Australian children
    Bjarte Furnes
    National Centre for Reading Education and Research, University of Stavanger, Stavanger, Norway
    Dyslexia 16:119-42. 2010
    ....
  30. pmc Dynamic and static assessment of phonological awareness in preschool: a behavior-genetic study
    William L Coventry
    University of New England, Armidale, Australia
    J Learn Disabil 44:322-9. 2011
    ....
  31. pmc What influences literacy outcome in children with speech sound disorder?
    Robin L Peterson
    Department of Psychology, University of Denver, Denver, CO, USA
    J Speech Lang Hear Res 52:1175-88. 2009
    ..The authors report the literacy of children with SSD at ages 7-9, compared with controls and national norms, and relative to language skill and SSD persistence (both measured at age 5-6)...
  32. pmc The heritability of general cognitive ability increases linearly from childhood to young adulthood
    C M A Haworth
    Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King s College London, De Crespigny Park, London, UK
    Mol Psychiatry 15:1112-20. 2010
    ....
  33. pmc Genetic covariation between brain volumes and IQ, reading performance, and processing speed
    Rebecca S Betjemann
    Department of Psychology, D 12, Regis University, 3333 Regis Blvd, Denver, CO 80221, USA
    Behav Genet 40:135-45. 2010
    ..64), and white matter (r (g) = .89), but not prefrontal cortex. The only brain measure to share genetic influence with reading was total brain volume (r (g) = .32), which also shared genetic influences with processing speed...
  34. pmc Differential genetic etiology of reading difficulties as a function of IQ: an update
    S J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA
    Behav Genet 40:751-8. 2010
    ..75 (±.12) and .50 (±.10), respectively (p ≤ .045). These results suggest that reading difficulties in children with a higher IQ are due substantially to genetic influences and may require intensive remediation efforts...
  35. ncbi Etiology of the stability of reading difficulties: the longitudinal twin study of reading disabilities
    Raven L Astrom
    Institute for Behavioral Genetics, Department of Psychology, University of Colorado, Boulder, Colorado 80309, United States of America
    Twin Res Hum Genet 10:434-9. 2007
    ..65, indicating that common genetic influences account for approximately 75% of the stability between reading measures at the two time points...
  36. ncbi Understanding comorbidity: a twin study of reading disability and attention-deficit/hyperactivity disorder
    Erik G Willcutt
    University of Colorado at Boulder, Boulder, Colorado 80309, USA
    Am J Med Genet B Neuropsychiatr Genet 144:709-14. 2007
    ....
  37. ncbi Genetic and environmental influences on word recognition and spelling deficits as a function of age
    Angela Friend
    Department of Psychology, 345 UCB, University of Colorado at Boulder, Boulder, CO 80309, USA
    Behav Genet 37:477-86. 2007
    ..However, the tests for an interaction between genetic influences on word recognition and spelling deficits as a function of age were not significant...
  38. ncbi Genes, language development, and language disorders
    Shelley D Smith
    Department of Pediatrics, University of Nebraska Medical Center, Omaha, Nebraska 68198 5456, USA
    Ment Retard Dev Disabil Res Rev 13:96-105. 2007
    ..Understanding these processes can form the basis for refined procedures for diagnosis and treatment...
  39. ncbi Processing speed deficits in attention deficit/hyperactivity disorder and reading disability
    Michelle A Shanahan
    Department of Psychology, University of Denver, Denver, Colorado, USA
    J Abnorm Child Psychol 34:585-602. 2006
    ....
  40. ncbi From single to multiple deficit models of developmental disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, 2155 S Race St, Denver, CO 80208, USA
    Cognition 101:385-413. 2006
    ..It describes how this model evolved out of our attempts to understand two comorbidities, those between dyslexia and attention deficit hyperactivity disorder (ADHD) and between dyslexia and speech sound disorder (SSD)...
  41. ncbi Breakthroughs in the search for dyslexia candidate genes
    Lauren M McGrath
    University of Denver, Department of Psychology, Frontier Hall, 2155 S Race St, Denver, CO 80208, USA
    Trends Mol Med 12:333-41. 2006
    ..When causal variants are identified, they will need to be considered within a multifactorial framework, which is likely to involve gene-gene and gene-environment interactions, to make accurate predictions of diagnostic status...
  42. ncbi Genetic etiology of reading difficulties in boys and girls
    Sally J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado 80309, USA
    Twin Res Hum Genet 8:594-601. 2005
    ..3). A test for qualitative gender differences was also nonsignificant. Thus, these results provide little evidence for a differential genetic etiology of RD in boys and girls...
  43. pmc DCDC2 is associated with reading disability and modulates neuronal development in the brain
    Haiying Meng
    Department of Pediatrics, Yale Child Health Research Center, Yale University School of Medicine, New Haven, CT 06520, USA
    Proc Natl Acad Sci U S A 102:17053-8. 2005
    ..The statistical and functional studies are complementary and are consistent with the latest clinical imaging data for RD. Thus, we propose that DCDC2 is a candidate gene for RD...
  44. ncbi Bivariate linkage scan for reading disability and attention-deficit/hyperactivity disorder localizes pleiotropic loci
    J Gayan
    Wellcome Trust Centre for Human Genetics, University of Oxford, UK
    J Child Psychol Psychiatry 46:1045-56. 2005
    ....
  45. ncbi TDT-association analysis of EKN1 and dyslexia in a Colorado twin cohort
    Haiying Meng
    Department of Pediatrics, Yale Child Health Research Center, Yale University School of Medicine, 464 Congress Avenue, New Haven, CT 06520 8081, USA
    Hum Genet 118:87-90. 2005
    ..Alternatively, the published findings of association with markers in EKN1 may reflect linkage disequilibrium with variation in another gene(s) in the region...
  46. ncbi Analyzing comorbidity
    Bruce F Pennington
    Department of Psychology, University of Denver, Denver, CO 80208, USA
    Adv Child Dev Behav 33:263-304. 2005
  47. ncbi Causal heterogeneity in attention-deficit/hyperactivity disorder: do we need neuropsychologically impaired subtypes?
    Joel T Nigg
    Department of Psychology, Michigan State University, East Lansing, Michigan 48824, USA
    Biol Psychiatry 57:1224-30. 2005
    ....
  48. ncbi Toward a new neuropsychological model of attention-deficit/hyperactivity disorder: subtypes and multiple deficits
    Bruce F Pennington
    Department of Psychology, University of Denver, Denver, CO 80210 4638, USA
    Biol Psychiatry 57:1221-3. 2005
  49. pmc Testing for neuropsychological endophenotypes in siblings discordant for attention-deficit/hyperactivity disorder
    L Cinnamon Bidwell
    Department of Psychology, University of Colorado, Boulder, Colorado, USA
    Biol Psychiatry 62:991-8. 2007
    ..Neurocognitive deficits associated with attention-deficit/hyperactivity disorder (ADHD) might be useful intermediate endophenotypes for determining specific genetic pathways that contribute to ADHD...
  50. ncbi Test of alternative hypotheses explaining the comorbidity between attention-deficit/hyperactivity disorder and conduct disorder
    Soo Hyun Rhee
    Department of Psychology, University of Colorado, Boulder, CO 80309, USA
    J Abnorm Child Psychol 36:29-40. 2008
    ..The results suggest that correlated risk factors are a better explanation for the comorbidity between ADHD and CD than a third, independent ADHD+CD subtype...
  51. ncbi Brain structure correlates of component reading processes: implications for reading disability
    Erin Phinney
    Department of Psychology, University of Denver, Denver, CO 80208, USA
    Cortex 43:777-91. 2007
    ....
  52. pmc Does classroom separation affect twins' reading ability in the early years of school?
    William L Coventry
    School of Behavioural, Cognitive and Social Sciences, University of New England, Armidale, Australia
    Twin Res Hum Genet 12:455-61. 2009
    ..We conclude that, on average, early literacy in twins is not directly affected by their assignment to the same or different classrooms...
  53. pmc How word decoding skill impacts text memory: The centrality deficit and how domain knowledge can compensate
    Amanda C Miller
    Department of Psychology, University of Denver, CO 80208, USA
    Ann Dyslexia 59:99-113. 2009
    ..This presents an exciting avenue to pursue for possible remediation of reading comprehension in children with word identification difficulties...
  54. pmc Gender ratios for reading difficulties
    Jesse L Hawke
    Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
    Dyslexia 15:239-42. 2009
    ....
  55. pmc A twin study of the genetics of high cognitive ability selected from 11,000 twin pairs in six studies from four countries
    Claire M A Haworth
    Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King s College London, London, UK
    Behav Genet 39:359-70. 2009
    ..41-0.60). Shared environmental influences were moderate (0.28, 0.19-0.37). We conclude that genetic variation contributes substantially to high g in Australia, the Netherlands, the United Kingdom and the United States...
  56. pmc Heritability of high reading ability and its interaction with parental education
    Angela Friend
    Department of Psychology, University of Colorado at Boulder, Boulder, CO 80309, USA
    Behav Genet 39:427-36. 2009
    ..This result provides a coherent account when considered alongside results of previous research showing that heritability for low reading ability decreased with lower levels of parental education...
  57. pmc Gene X environment interactions in reading disability and attention-deficit/hyperactivity disorder
    Bruce F Pennington
    Department of Psychology, University of Denver, USA
    Dev Psychol 45:77-89. 2009
    ..However, they did not find a G x E interaction at the favorable end of the ADHD symptom dimension. The authors conclude with implications for future research...
  58. doi How neuropsychology informs our understanding of developmental disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, 2155 S Race Street, Denver, Colorado 80208 4403, USA
    J Child Psychol Psychiatry 50:72-8. 2009
    ....
  59. pmc Parental education moderates genetic influences on reading disability
    Angela Friend
    Department of Psychology, University of Colorado at Boulder, Boulder, CO 80309, USA
    Psychol Sci 19:1124-30. 2008
    ..We discuss the implications of these results for behavior genetic and molecular genetic research, for the diagnosis and remediation of reading disabilities, and for policy in public education...
  60. ncbi Phonological and semantic priming in children with reading disability
    Rebecca S Betjemann
    Institute for Behavioral Genetics, University of Colorado, UCB 447, Boulder, CO 80309 0447, USA
    Child Dev 79:1086-102. 2008
    ..These semantic deficits may contribute to both the word reading and the comprehension problems seen in children with RD...
  61. ncbi Relations among speech, language, and reading disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, Colorado 80208, USA
    Annu Rev Psychol 60:283-306. 2009
    ..We evaluate which comorbidity models can be rejected or supported as explanations for why and how these three disorders overlap and what new data are needed to better define their relations...
  62. ncbi Do motivational incentives reduce the inhibition deficit in ADHD?
    Michelle A Shanahan
    Department of Psychology, University of Denver, CO 80208 0001, USA
    Dev Neuropsychol 33:137-59. 2008
    ..Hence, as predicted by the inhibition theory, children with ADHD performed worse than controls irrespective of incentives...
  63. ncbi DeFries-Fulker and Pearson-Aitken model-fitting analyses of reading performance data from selected and unselected twin pairs
    Jesse L Hawke
    Institute for Behavioral Genetics, University of Colorado, Boulder, 447 UCB, Boulder, CO 80309 0447, US
    Behav Genet 38:101-7. 2008
    ..However, the PA selection formula may be more readily generalized to the multivariate case...
  64. ncbi Colorado longitudinal twin study of reading disability
    Sally J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, 447 UCB, Boulder, CO 80309, USA
    Ann Dyslexia 57:139-60. 2007
    ..In addition, genetic correlations reached unity for both groups, suggesting that the same genetic influences are manifested at both time points...
  65. ncbi Genes, environment, and dyslexia. The 2005 Norman Geschwind Memorial Lecture
    Richard K Olson
    Department of Psychology, University of Colorado, UCB 345, Boulder, CO 80309, USA
    Ann Dyslexia 56:205-38. 2006
    ....
  66. ncbi Neuropsychological analyses of comorbidity between reading disability and attention deficit hyperactivity disorder: in search of the common deficit
    Erik G Willcutt
    Department of Psychology, University of Colorado at Boulder, CO 80309, USA
    Dev Neuropsychol 27:35-78. 2005
    ..Slow and variable processing speed was characteristic of all 3 clinical groups, suggesting that measures of this domain may be useful for future studies that search for the common genes that increase susceptibility to RD and ADHD...